1. Field of the Invention
The present invention relates to image processing method and apparatus for managing digital image data, and more particularly to image processing method and apparatus having plural functions such as a copy function, a facsimile function, a print function and the like.
2. Related Background Art
Recently, in respect of an image processing apparatus such as a digital copy machine or the like, a so-called digital multi-functional apparatus having not only the copy function but also the print function and the facsimile function has been developed. Since the digital multi-functional apparatus is the machine to perform a digital image process, such the apparatus can be easily added with the above plural functions. Further, since the multi-functional apparatus can perform the above plural functions by itself, such advantages as saving space and increasing operational efficiency can be derived.
In the digital multi-functional apparatus, generally an image process dedicated digital arithmetic processing unit performs the image process. Such the unit can perform a high-speed process as outputting several tens of images per minute.
However, the above digital arithmetic processing unit has been designed on the premise that it processes sequential image signals to realize high-speed arithmetic processing. Therefore, in such an aspect as performing plural different image processes in parallel, it has been difficult to generalize the above unit.
More particularly, in FIGS. 5A to 5C showing a format of image signal in the image process dedicated digital arithmetic processing unit, FIG. 5A is directed to a data line representing each pixel. In the drawing, each pixel has an information amount of eight bits and is expressed as a signal synchronized with an image clock. FIG. 5B is directed to line data having a certain length in which the respective pixels are linked together. FIG. 5C is directed to a format of image signal under such a situation as each line data is repeated with the same length and at the same timing.
This image signal belongs to a signal system independent of a control signal of a central processing unit (CPU), and does not directly synchronize with a control program of the CPU. Further, an image clock and line data are repeated respectively at remarkably rapid periods, e.g., about 10 MHz in the clock and about 400 micro seconds in the data. Therefore, in order to perform the plural functions in parallel, it is necessary that the CPU changes setting of various parameters concerning the image process for each pixel or each line data. For this reason, since the CPU has terminated the necessary setting before the image process of a first page starts, the CPU ordinarily does not participate in the process itself during image data is actually processed.
Therefore, in case of structuring the multi-functional apparatus as above, it is difficult to simultaneously process the plural functions in parallel. Namely, controllable frequency and precision in setting of the image process are limited, so that there has been such a problem as the process can be changed only in large-job unit such as one-page unit.
If it is intended to smoothly and simultaneously process the plural functions in parallel by avoiding the above problem, it is necessary to provide several circuits having same functions, so that there has been such a problem as a structure of the apparatus becomes more complicated and expensive.